TURNOVER OF INOSITOL AND PHOSPHORUS CONTAINING LIPIDS IN SACCHAROMYCES-CEREVISIAE - EXTRACELLULAR ACCUMULATION OF GLYCEROPHOSPHORYLINOSITOL DERIVED FROM PHOSPHATIDYLINOSITOL
TURNOVER OF INOSITOL AND PHOSPHORUS CONTAINING LIPIDS IN SACCHAROMYCES-CEREVISIAE - EXTRACELLULAR ACCUMULATION OF GLYCEROPHOSPHORYLINOSITOL DERIVED FROM PHOSPHATIDYLINOSITOL
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DOI：
10.1016/0003-9861(72)90525-5
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发表时间：
1972-01-01
影响因子：
3.9
通讯作者：
LESTER, RL
中科院分区：
文献类型：
--
作者：
ANGUS, WW;LESTER, RL
用均一标记的~(32)P和[2-H]肌醇对酵母细胞进行的周转实验表明，主要含肌醇的化合物磷脂酰肌醇以相同的速率丢失这两种标记，半衰期约为两代。相反，32P在磷脂酰胆碱中积累，推测来自脂肪和非脂质前体。主要的酵母磷脂，神经酰胺(肌醇)2(磷酸)2甘露糖同时积累~H和~(32)P，表明磷脂酰肌醇是磷脂酰肌醇的前体，在此转化过程中，磷和肌醇之间的键没有断裂。在对数生长过程中，酵母菌在复杂或特定的培养基上释放一种含有肌醇的化合物，我们将其鉴定为甘油磷脂肌醇(GPI)。释放量与细胞密度成正比，相当于细胞磷脂酰肌醇的1/4。与GPI相比，培养液中积累的甘油磷酰胆碱(GPC)和甘油磷酰乙醇胺(GPE)要少得多。GPI、GPE和GPC未被细胞重复利用。胞外GPI在周转实验中以相同的速率获得~(32)H和~(32)P标记，表明它也是磷脂酰肌醇周转的产物，可能是通过直接脱酰作用。在[2-3 H]肌醇存在下生长的酵母菌中，88%的3 H是酸不溶的，可以被回收为脂肪，99%的可提取的3 H仍在肌醇中。在分析的化合物中发现的总的~H在周转过程中是恒定的，这表明所有定量上重要的肌醇池都被测量了。
A turnover experiment was performed with yeast cells uniformly labeled with both 32 P and [2-3 H] inositol showing that the major inositol-containing compound phosphatidylinositol lost both labels at the same rate with a half life of about two generations. In contrast, 32 P accumulated in phosphatidylcholine, presumably derived from lipid and nonlipid precursors. The major yeast phosphosphingolipid, ceramide (inositol) 2 (phosphate) 2 mannose accumulated both 3 H and 32 P at a rate suggesting that phosphatidylinositol served as the phosphoinositol precursor and that the bond between phosphorus and inositol is not broken during this conversion. During logarithmic growth, on complex or defined media, yeast release an inositol-containing compound, which we identified as glycerophosphorylinositol (GPI). The amount released was proportional to cell density and equivalent to 1 4 the cellular phosphatidylinositol. Compared to GPI, much smaller amounts of glycerophosphorylcholine (GPC) and glycerophosphorylethanolamine (GPE) accumulated in the medium. GPI, GPE and GPC were not reutilized by the cells. Extracellular GPI acquired both 3 H and 32 P labels at the same rate during the turnover experiment, indicating that it too is a product of phosphatidylinositol turnover, presumably via direct deacylation. With yeast grown in the presence of [2-3 H] inositol, 88% of the 3 H was acid insoluble and could be recovered as lipid; 99% of the lipid-extractable 3 H was still in inositol. The total 3 H found in the compounds analyzed was constant during the turnover suggesting that all quantitatively important pools of inositol were measured.